Hole cutter with chip egress aperture

Abstract

A hole cutter has a substantially cylindrical blade body defining a blade body circumference, a cutting edge formed on one end of the blade body, and an axially-elongated slot formed through the substantially cylindrical blade body. The axially-elongated slot is configured to receive chips flowing from the cutting edge within the interior of the blade body and (i) into the slot and/or (ii) through the slot, to prevent the collection of such chips within the interior of the blade body and/or at an interface between the blade body and the work piece. The axially-elongated slot defines a first end adjacent to the cutting edge, a second end axially spaced further from the cutting edge, and a slot area. The hole cutter further defines a total slot area to blade body circumference ratio within the range of about 0.1 to about 0.3 depending on the size of the hole cutter.

What is claimed is: 
     
       1. A hole cutter for cutting a work piece, comprising:
 a substantially cylindrical blade body defining a cutting edge and a longitudinal axis; 
 a first aperture portion formed through the blade body and spaced from the cutting edge such that a portion of the blade body extends between the cutting edge and the first aperture portion, the first aperture portion configured to receive therethrough a lever for removing a work piece slug from an interior of the blade body and defining a first fulcrum configured for engaging the lever and for levering the slug out of the interior of the blade body; and 
 a second aperture portion formed through the blade body and spaced from the cutting edge such that a portion of the blade body extends between the cutting edge and the second aperture portion, the second aperture portion configured to receive therethrough a lever for removing a work piece slug from an interior of the blade body and defining a second fulcrum configured for engaging the lever and for levering the slug out of the interior of the blade body by applying a sufficient levering force against the second fulcrum to lever the slug towards the cutting edge, 
 wherein the first fulcrum is axially spaced from the cutting edge a first distance, the second fulcrum is axially spaced from the cutting edge a second distance that is greater than the first distance, and 
 wherein the first aperture portion and the second aperture portion together define an aperture area, and wherein one of: (i) the blade body defines a diameter within the range of about ⅞ inch to about 1 7/16 inches, and a ratio of the aperture area to the blade body circumference is between about 0.18 and about 0.31; (ii) the blade body defines a diameter within the range of about 1½ inches to about 3⅜ inches, and a ratio of the aperture area to the blade body circumference is between about 0.10 and about 0.24; and (iii) the blade body defines a diameter of about 3½ inches or greater, and a ratio of the aperture area to the blade body circumference is between about 0.11 and about 0.21. 
 
     
     
       2. The hole cutter of  claim 1 , wherein the first aperture portion is in communication with the second aperture portion via a slot portion. 
     
     
       3. The hole cutter of  claim 1 , wherein at least a portion of the first aperture portion and at least a portion of the second aperture portion are aligned along a line substantially parallel to the longitudinal axis. 
     
     
       4. The hole cutter of  claim 1 , wherein at least one of the first aperture portion and the second aperture portion is bounded by a bottom edge axially spaced a third distance from the cutting edge, a top edge spaced a fourth distance from the cutting edge greater than the third distance, and a side edge connecting the bottom edge to the top edge and oriented at an acute angle to the longitudinal axis of the blade body. 
     
     
       5. The hole cutter of  claim 1 , wherein the first fulcrum is defined by a first bottom edge of the first aperture portion that is substantially parallel to the cutting edge and wherein the second fulcrum is defined by a second bottom edge of the second aperture portion that is substantially parallel to the cutting edge. 
     
     
       6. The hole cutter of  claim 5 , wherein the first aperture portion further includes a first top edge that is generally parallel to the first bottom edge and that is spaced from the cutting edge. 
     
     
       7. The hole cutter of  claim 6 , wherein the second aperture portion includes a second bottom edge that is generally parallel to the cutting edge and that defines the second fulcrum and second top edge that is generally parallel to the second bottom edge and that is spaced from the cutting edge. 
     
     
       8. The hole cutter of  claim 1 , wherein each of the first aperture portion and the second aperture defines a minimum width to allow insertion of a number  2  screwdriver therethrough. 
     
     
       9. The hole cutter of  claim 1 , wherein the second fulcrum is angularly spaced around a circumference of the blade body relative to the first fulcrum. 
     
     
       10. The hole cutter of  claim 1 , wherein the first aperture portion is axially elongated. 
     
     
       11. A hole cutter for cutting a work piece, comprising:
 a substantially cylindrical blade body defining a cutting edge and a longitudinal axis; 
 a first aperture portion formed through the blade body and spaced from the cutting edge such that a portion of the blade body extends between the cutting edge and the first aperture portion, the first aperture portion configured to receive therethrough a lever for removing a work piece slug from an interior of the blade body and defining a first fulcrum configured for engaging the lever and for levering the slug out of the interior of the blade body; and 
 a second aperture portion formed through the blade body and spaced from the cutting edge such that a portion of the blade body extends between the cutting edge and the second aperture portion, the second aperture portion configured to receive therethrough a lever for removing a work piece slug from an interior of the blade body and defining a second fulcrum configured for engaging the lever and for levering the slug out of the interior of the blade body by applying a sufficient levering force against the second fulcrum to lever the slug towards the cutting edge, 
 wherein the first fulcrum is axially spaced from the cutting edge a first distance, the second fulcrum is axially spaced from the cutting edge a second distance that is greater than the first distance, and 
 wherein the first aperture portion and the second aperture portion together define an aperture area, and wherein one of: (i) the blade body defines a diameter within the range of about ⅞ inch to about 1 7/16 inches, and the aperture area is between about 10% and about 15% of the blade body area; (ii) the blade body defines a diameter within the range of about 1½ inches to about 3⅜ inches, and the aperture area is between about 6% and about 13% of the blade body area; and (iii) the blade body defines a diameter of about 3½ inches or greater, and the aperture area is between about 6% and about 11% of the blade body area. 
 
     
     
       12. The hole cutter of  claim 11 , wherein the first aperture portion is in communication with the second aperture portion via a slot portion. 
     
     
       13. The hole cutter of  claim 11 , wherein at least a portion of the first aperture portion and at least a portion of the second aperture portion are aligned along a line substantially parallel to the longitudinal axis. 
     
     
       14. The hole cutter of  claim 11 , wherein at least one of the first aperture portion and the second aperture portion is bounded by a bottom edge axially spaced a third distance from the cutting edge, a top edge spaced a fourth distance from the cutting edge greater than the third distance, and a side edge connecting the bottom edge to the top edge and oriented at an acute angle to the longitudinal axis of the blade body. 
     
     
       15. The hole cutter of  claim 11 , wherein the first fulcrum is defined by a first bottom edge of the first aperture portion that is substantially parallel to the cutting edge and wherein the second fulcrum is defined by a second bottom edge of the second aperture portion that is substantially parallel to the cutting edge. 
     
     
       16. The hole cutter of  claim 15 , wherein the first aperture portion further includes a first top edge that is generally parallel to the first bottom edge and that is spaced from the cutting edge. 
     
     
       17. The hole cutter of  claim 16 , wherein the second aperture portion includes a second bottom edge that is generally parallel to the cutting edge and that defines the second fulcrum and second top edge that is generally parallel to the second bottom edge and that is spaced from the cutting edge. 
     
     
       18. The hole cutter of  claim 11 , wherein each of the first aperture portion and the second aperture defines a minimum width to allow insertion of a number  2  screwdriver therethrough. 
     
     
       19. The hole cutter of  claim 11 , wherein the second fulcrum is angularly spaced around a circumference of the blade body relative to the first fulcrum. 
     
     
       20. The hole cutter of  claim 11 , wherein the first aperture portion is axially elongated.